Darlington transistors are compound semiconductor devices consisting of two bipolar junction transistors (BJTs) connected together to function as a single unit. This configuration provides extremely high current gain, allowing a very small base current to control a much larger collector current. Darlington transistors are ideal for applications requiring high amplification, such as motor controllers, light dimmers, audio amplifiers, and relay drivers. While they offer excellent sensitivity and gain, they have a higher voltage drop and slower switching speed compared to single transistors. Their ease of use and amplification strength make them valuable in many power and control circuits.